v1::text_shaper_char Class Reference

Public Member Functions
	text_shaper_char (hi::grapheme const &grapheme, text_style const &style, hi::pixel_density pixel_density) noexcept
void	initialize_glyph (hi::font const &font) noexcept
	Initialize the glyph based on the grapheme.
void	initialize_glyph () noexcept
	Initialize the glyph based on the grapheme.
void	replace_glyph (char32_t code_point) noexcept
	Called by the bidi-algorithm to mirror glyphs.
font_metrics_px	font_metrics () const noexcept
	Get the scaled font metrics for this character.

Data Fields
hi::grapheme	grapheme
	The grapheme.
hi::text_style	style
	The style of how to display the grapheme.
pixel_density	pixel_density
	The scale to resize the font's size to match the physical display.
hi::font_book::font_glyphs_type	glyphs
	The glyph representing one or more graphemes.
hi::glyph_metrics	metrics
	The glyph metrics of the current starter glyph.
size_t	line_nr
	The line number where this character is located, counting from top to bottom line.
size_t	column_nr
	The column number where the character is located on the line, counting from left to right in display order.
point2	position
	Position of the character.
aarectangle	rectangle
	The rectangle for this character.
unicode_general_category	general_category
	The general category of this grapheme.
unicode_bidi_class	direction
	The text direction for this glyph.
iso_15924	script
	The script of this character.
au::Quantity< PixelsPerEm, float >	font_size
	The font size in pixels, rounded so that the x-height is rounded to the nearest pixel.
float	width = 0.0f
	The width used for this grapheme when folding lines.
bool	is_trailing_white_space = false
	Set to true if this glyph is a white space at the end of a line.
bool	glyph_is_initial = false
	The glyph is the initial glyph.

Friends
bool	operator== (text_shaper_char const &lhs, char32_t const &rhs) noexcept
bool	operator== (text_shaper_char const &lhs, char const &rhs) noexcept

Member Function Documentation

font_metrics()

font_metrics_px v1::text_shaper_char::font_metrics ( ) const

inlinenoexcept

Get the scaled font metrics for this character.

initialize_glyph() [1/2]

void v1::text_shaper_char::initialize_glyph ( )

inlinenoexcept

Initialize the glyph based on the grapheme.

Note

The glyph is only initialized when glyph_is_initial == false.

Postcondition

glyph, metrics and width are modified. glyph_is_initial is set to true.

initialize_glyph() [2/2]

void v1::text_shaper_char::initialize_glyph ( hi::font const & font )

inlinenoexcept

Initialize the glyph based on the grapheme.

Note

The glyph is only initialized when glyph_is_initial == false.

Postcondition

glyph, metrics and width are modified. glyph_is_initial is set to true.

replace_glyph()

void v1::text_shaper_char::replace_glyph ( char32_t code_point )

inlinenoexcept

Called by the bidi-algorithm to mirror glyphs.

The glyph is replaced with a glyph from the same font using the given code-point.

Precondition

glyph.num_grapheme == 1.

Postcondition

glyph and metrics are modified. glyph_is_initial is set to false.

Note

The width remains based on the original glyph.

Field Documentation

column_nr

size_t v1::text_shaper_char::column_nr

The column number where the character is located on the line, counting from left to right in display order.

direction

unicode_bidi_class v1::text_shaper_char::direction

The text direction for this glyph.

This is needed to figure out where the location of the insert cursor is compared to the character.

font_size

au::Quantity<PixelsPerEm, float> v1::text_shaper_char::font_size

The font size in pixels, rounded so that the x-height is rounded to the nearest pixel.

general_category

unicode_general_category v1::text_shaper_char::general_category

The general category of this grapheme.

glyph_is_initial

bool v1::text_shaper_char::glyph_is_initial = false

The glyph is the initial glyph.

This flag is set to true after loading the initial glyph. This flag is set to false when the glyph is replaced by the bidi-algorithm or glyph-morphing.

glyphs

hi::font_book::font_glyphs_type v1::text_shaper_char::glyphs

The glyph representing one or more graphemes.

The glyph will change during shaping of the text:

1. The starter glyph, used for determining the width of the grapheme and the folding algorithm.
2. The glyph representing a bracket may be replaced with a mirrored bracket by the bidi-algorithm.
3. The glyph may be replaced by the font using the glyph-morphing algorithms for better continuation of cursive text and merging of graphemes into a ligature.

grapheme

hi::grapheme v1::text_shaper_char::grapheme

The grapheme.

is_trailing_white_space

bool v1::text_shaper_char::is_trailing_white_space = false

Set to true if this glyph is a white space at the end of a line.

line_nr

size_t v1::text_shaper_char::line_nr

The line number where this character is located, counting from top to bottom line.

metrics

hi::glyph_metrics v1::text_shaper_char::metrics

The glyph metrics of the current starter glyph.

The metrics are scaled by scale.

pixel_density

pixel_density v1::text_shaper_char::pixel_density

The scale to resize the font's size to match the physical display.

position

point2 v1::text_shaper_char::position

Position of the character.

For a non-ligature this is the origin of the glyph, where the actual glyph is located at position + metrics.bounding_rectangle. For ligatures the position is moved based on the advance of each character within the ligature.

rectangle

aarectangle v1::text_shaper_char::rectangle

The rectangle for this character.

The rectangle is used for:

• creating a selection box around the character.
• creating cursors before, after and on the character.
• converting mouse-position to character.

The attributes of the rectangle are:

• left side is equal to the position.x
• The width is the advance of the character within the ligature. Or if the glyph is not a ligature the width is the same as the advance.
• The bottom is at the descender
• The top is at the ascender

When multiple characters are converted to a ligature, the rectangle of each of those characters occupies a subsection of the ligature-glyph. In this case the left most character will contain the ligature-glyph, and the rest of the characters of the ligature will have empty glyphs.

script

iso_15924 v1::text_shaper_char::script

The script of this character.

The script of the character is based on:

• The actual script of this unicode character, or if unicode_script::Common;
• The script of characters before/after this character in the same word, or if unicode_script::Common;
• The script passed during construction of the text_shaper.

style

hi::text_style v1::text_shaper_char::style

The style of how to display the grapheme.

width

float v1::text_shaper_char::width = 0.0f

The width used for this grapheme when folding lines.

This width is based on the initial glyph's advance after converting the grapheme using the text-style into a glyph. This width excludes kerning and glyph-morphing.

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The documentation for this class was generated from the following file:

• hikogui/src/hikogui/text/text_shaper_char.hpp